title: Mechanical stability of the AO internal spinal fixation system compared with that of the Hartshill rectangle and sublaminar wiring in the management of unstable burst fractures of the thoracic and lumbar spine.
abstract: METHODS
  A radiographic comparison of the mechanical efficacy of the Hartshill rectangle and that of the AO internal spinal skeletal fixation systems in the management of unstable burst fractures of the thoracic and lumbar spine.
  
  
  OBJECTIVE
  To study the restoration and maintenance of normal spinal anatomy after open reduction and internal fixation of unstable burst fractures of the thoracic and lumbar spine.
  
  
  BACKGROUND
  There are laboratory studies documenting the biomechanical advantages of the AO internal spinal skeletal fixation systems. There have been no previous comparisons of the internal spinal skeletal fixation system with the Hartshill rectangle and sublaminar wiring in matched patient groups.
  
  
  METHODS
  Radiographs obtained before surgery, immediately after surgery, and at 2 years after surgery were used to assess the restoration and maintenance of normal spinal anatomy in 14 patients who had undergone stabilization with the Hartshill System and in 12 patients who had undergone internal fixation using the AO internal spinal skeletal fixation system.
  
  
  RESULTS
  The initial restoration of normal spinal anatomy was good using both systems. However, on examination 2 years after surgery, it was found that the AO system provided significantly superior maintenance of both middle (P < 0.01) and anterior column anatomy (P < 0.001).
  
  
  CONCLUSIONS
  The AO internal spinal skeletal fixation systems is associated with significantly superior maintenance of spinal anatomy 2 years after surgery.
authors.affiliation: Royal Preston Hospital, Lancashire, England.
authors.forename: T R
authors.initials: TR
authors.lastname: Cresswell
authors.forename: P D
authors.initials: PD
authors.lastname: Marshall
authors.forename: R B
authors.initials: RB
authors.lastname: Smith
mesh_terms: D001863:Bone Screws; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D012189:Retrospective Studies; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed